Currently, all fopen uses in mpv do not set cloexec flag, resulting
in fd leak whenever mpv creates a process.
This makes mpv use mp_fopen on all platforms, and always set O_CLOEXEC
on the opened fd. This is required because the "e" flag for fopen is
nonstandard and UB in C11, and unsupported on macOS.
This had been done similarly in other projects. e.g.
https://gitlab.com/graphviz/graphviz/-/merge_requests/3797
The previous commit to dynamically load VapourSynth R74 would fail to work
for VapourSynth R73 and before on Linux due to load mode RTLD_LOCAL. To
make it work on all VapourSynth version, switch to use RTLD_GLOBAL mode.
Add library handle closing in drv_vss_uninit for completeness.
The dynamic allocation of this strings is completelly pointless. It adds
complexity with mp_exec_once to init aexit() to free the string, which
was leaked anyway, because the structure is thread_local and atexit only
data from the main thread was freed.
Remove all this, and just use static buffer.
C11 uses _Thread_local as the keyword, which thread_local macro
is defined to (inside of <threads.h>, which mpv doesn't use):
https://port70.net/~nsz/c/c11/n1570.html#7.26.1p3
C23 promotes thread_local to a keyword and marks _Thread_local
as obsolete and to be avoided in new code:
https://www.iso-9899.info/n3220.html#6.4.1p3
so just use thread_local directly, which is future-proof while
having a fallback define in osdep/threads.h for pre-C23 cases.
Trivial wrapper around _chsize_s() to return -1 on errors always.
_chsize_s() returns errno value. At the same time errno is set to the
same value.
FILE_WRITE_DATA has to be added in append mode, because _chsize_s()
requires write permissions, not only append. We lose atomic append, but
we follow POSIX here, so that's fine, I guess.
Removes mp_puts/mp_fputs and adds mp_fwrite.
In fact I wanted fwrite instead of puts, no need to make it more awkward
with the implicit new lines.
Fixes: fc55f355fc
GetConsoleMode() can be quite slow and in mpv the mode never changes, so
we can just check it once.
Fixes performance when writing lots of logs to terminal.
This flag is a GNU extension in C99, but was standardrized in C11,
so mpv should be able to use it. fopen is wrapped on win32 so
non-compliant MSVCRT.dll isn't a concern.
Since the upcoming commit uses this feature it can be brought back.
This reverts commit c36e051470.
unlink() was never wrapped in win32, so all usages of it were referring
the ANSI version of the function. This doesn't work properly for Windows
versions before 1903 (where the UTF-8 codepage is requested).
Fix this by adding mp_unlink() which wraps over _wunlink().
The purpose of osdep/io is to provide a wrapper for POSIX I/O functions
on Windows. The last 2 functions are utility functions which don't serve
this purpose.
Move them to a separate file.
fopen() with 'x' mode is a non-portable glibc extension, is currently
unused, and should not be used in order to maintain POSIX compatibility.
Thus there is no need for the Windows wrapper mp_fopen() to support it.
Add xoshiro as a PRNG implementation instead of relying
on srand() and rand() from the C standard library. This,
in particular, lets us avoid platform-defined behavior with
respect to threading.
lua/js utils.get_env_list() uses `environ' which was ANSI, thus
it broke any unicode names/values.
mpv already has an internal utf8_environ for win32, but it's used
only at the getenv(..) wrapper and not exposed in itself, and also it
has lazy initialization - on first getenv() call.
Now `environ' maps to a function which ensures initialization while
keeping it an l-value (like posix expects).
The cost of this fuglyness is that files should include osdep/io.h
(which now declares environ as extern) rather than declaring it
themselves, or else the build will break on mingw.
Unused now. The old stream cache used it, but it was removed.
On a side note, the demuxer cache uses mp_mkostemps(). It looks like our
Windows open() emulation handles this correctly by using CREATE_NEW, so
no functionality gets lost by the "new" approach. On the other hand, the
demuxer cache does not set FILE_FLAG_DELETE_ON_CLOSE, but instead tries
to delete the file after opening (POSIX style), which probably won't
work on Windows. But I'm not sure how to make it use the DELETE_ON_CLOSE
flag, so whatever.
Supposed to follow the standard function.
The standard function is not standard, but a GNU extension. Adding some
ifdef mess is pointless too - it has no advantages other than having a
mess, and not spotting implementation bugs in the emulation due to
running it only on "obscure" platforms (like Windows, so most computers
actually, except the developer's platform).
There is mkstemp(), which at least is in POSIX 2008. But it's 100%
useless, except in some obscure cases: it doesn't set O_CLOEXEC, nor can
you pass it to it. Without O_CLOEXEC, we'd leak the temporary file to
all child processes. (The fact that the file, which is expected to reach
double or tripple digit GB sizes, will be deleted only once all
processes unreference the FD, makes this sort of a big deal. You could
ftruncate() it, but that doesn't fix all the other problems.)
Why did POSIX standardize mkstemp() and O_CLOEXEC apparently at the same
time, but provided no way to pass O_CLOEXEC to mkstemp()? With the
introduction of O_CLOEXEC, they acknowledged that there's a need to
atomically set the FD_CLOEXEC flag when creating file descriptors.
(FD_CLOEXEC was standard before that, but setting it with fcntl() is
racy.) You're much more likely to need a temp file that is CLOEXEC
rather than the opposite, and even if they were somehow opposed to
CLOEXEC by default (such as for compat. reasons), surely POSIX could
have standardized mkostemp() too or instead.
And then there's the fact that this whole O_CLOEXEC mess is stupid.
Surely there would have been a better way to handle this, instead of
requiring adding O_CLOEXEC to almost ALL instances of open() in all code
that has been written ever. The justification for this is that the
historic default was wrong, and you can't change it (e.g. this won't
work: changing the behavior of exec() and not inherit the FD to the
child process, unless a hypothetical O_KEEP_EXEC flag is set).
But on the other hand, surely you could have introduced an exec()
variant which does close all FDs, except a whitelist of FDs passed to
it. Let's call it execve2(). In fact, I'm going to argue that exec()
call sites are the most aware of whether (and which) FDs to inherit.
Some programs even tried to explicitly iterate over all opened FDs and
explicitly close "unwanted" FDs (which of course was problematic for
other reasons), and such an execve2() call would have been the ideal
solution.
Maybe this proposed solution would have had problems too. But surely
revisiting and reviewing every exec*() call would have been simpler than
reviewing every open() call. And more importantly, having to extend
every damn library function that either calls open() or creates FDs in
some other way, like mkstemp().
What argument are there going to be against this? That there will be
library code that can't keep working correctly with processes that use
the "old" exec? Well, what about all my legacy library code that uses
open() incorrectly, and that will break no matter what?
Well, I'm not going to claim that I can come up with better solutions
than POSIX (generally or in this case), but this situation is ABSOLUTELY
ATROCIOUS. It makes win32 programming look attractive compared to POSIX,
that standard pandering to dead people from the past. (Note: not trying
to insult dead people.)
I'm not sure what POSIX is even doing. Anything useful? Doesn't look
like it to me. Are they paid? Why? They didn't even fix the locale mess,
nor do they intend to. I bet they're proud of discussing compatibility
to 70ies code day in and day out iwtohut ever producing anything useful.
What a load of crap. They seriously got to do better than this.
Oh, and my wrapper is probably buggy. Fortunately that doesn't matter.
Also I'm dumping this into io.h. Originally, io.h was just supposed to
replace broken implementation of standard functions by MinGW (and then
by Android), but whatever, just give a dumping ground for shit code.
This sliences some warnings about unused values and statements with no
effect, but it also fixes a logic error with freelocale(), since
previously it would not work as expected when used in the body of an if
statement without braces.
Uses real functions, because with macros, I don't think there is a way
to silence the "statement with no effect" warnings in the case where the
return value of uselocale() is ignored.
As for replacing the these functions with working implementations, I
don't think this is possible for mpv's use-case, since MSVCRT does not
support UTF-8 locales, or any locale with multibyte characters that are
three or more bytes long. See:
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/setlocale-wsetlocale
Directory-opening never worked on Windows because MSVCRT's open()
doesn't open directories and its fstat() doesn't recognise directory
handles. These are just MSVCRT restrictions, and the Windows API itself
has no problem with opening directories as file objects, so reimplement
mpv's mp_open and mp_stat to use the Windows API directly. This should
fix directory playback.
This also populates the st_dev and st_ino fields of struct stat, so
filesystem loop checking in demux_playlist.c should now work on Windows.
Fixes#4711
nanahi